Antihyperglycemic and antioxidative potential of <Emphasis Type="Italic">Matricaria chamomilla</Emphasis> L. in streptozotocin-induced diabetic rats

Plants with antidiabetic activities provide important sources for the development of new drugs in the treatment of diabetes mellitus. In the present study, we investigated possible antihyperglycemic and antioxidative activities of the aerial part of the Matricaria chamomilla L. ethanolic extract (MCE) in streptozotocin (STZ; 70 mg/kg, i.p.)-induced diabetic rats. The following groups were assigned; sham (did not receive any substance), STZ + distilled water (control), STZ + 5 mg/kg glibenclamide, STZ + 20 mg/kg MCE, STZ + 50 mg/kg MCE, STZ + 100 mg/kg MCE. Diabetic rats were treated for 14 days by gavage. Postprandial blood glucose levels, malondialdehyde, reduced glutathione (GSH), nitrate, nitrite, ascorbic acid, retinol, β-carotene, superoxide dismutase, and catalase levels were measured, and immunohistochemical studies were performed in all of the groups. The obtained data showed that STZ resulted in oxidative stress and affected the antioxidant status. Treatment with different doses of MCE significantly reduced postprandial hyperglycemia and oxidative stress, and augmented the antioxidant system. In histological investigations, MCE treatment protected the majority of the pancreatic islet cells, with respect to the control group. As a result, MCE exhibited significant antihyperglycemic effect and protected β-cells in STZ-diabetic rats, in a dose-dependent manner, and diminished the hyperglycemia-related oxidative stress.     

Protective role of Dodonaea viscosa extract against streptozotocin-induced hepatotoxicity and nephrotoxicity in rats

Previous investigations have shown that D. viscosa herbal extract is often used to treat a variety of diseases. Therefore, the purpose of this study was to investigate any additional potential impacts on rat liver and kidney damage induced by diabetes. Streptozotocin (STZ) (60 mg/kg/day) was given as a single dosage to cause type 1 diabetes. After then, diabetic rats received oral doses of D. viscosa for four weeks at 150 and 300 mg/kg/day. Blood, liver, and kidney tissues were collected at the end of the treatment and examined. Analysis was made of the serum lipid profile, liver, and kidney functions, as well as blood biochemistry. Moreover, the levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), prostaglandin E-2 (PGE-2), and nitric oxide (NO) were estimated in serum. In liver and kidney samples, thiobarbituric acid reactive substances (TBARs) and reduced glutathione (GSH), as well as the pro-inflammatory cytokines and enzymatic activities of glutathione peroxidase (GPx), glutathione reeducates (GR), glutathione-S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) were analyzed. Histological changes in liver and kidney cross-sections were also observed. Our findings demonstrated that D. viscosa dramatically decreased pro-inflammatory indicators in blood, kidney, and liver tissues as well as blood glucose, and restored insulin levels, and lipid profiles. Additionally, it significantly raises the antioxidant enzyme activity SOD, CAT, GPx, and GST, while significantly lowering TBARs levels. The above-mentioned biochemical changes that took place in tissues were further supported by histological alterations. These findings imply that D. viscosa protects against STZ-induced hyperglycemia, aberrant lipid synthesis, and oxidative stress and that these benefits may be mediated by interacting with various targets to increase the levels of antioxidant enzymes in the liver and kidneys. Its mode of action and safety for use as medicine against various metabolic problems caused by diabetes require more research.     

Pancreatic tissue protective nature of D-Pinitol studied in streptozotocin-mediated oxidative stress in experimental diabetic rats

The present study was aimed to investigate the possible pancreatic tissue protective nature of D-Pinitol, a cyclitol present in soybean, against free radical-mediated oxidative stress in streptozotocin-induced diabetic rats by assaying the activity of pancreatic enzymatic antioxidants such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and glutathione-S-transferase (GST) and the levels of plasma non-enzymatic antioxidants such as vitamin E, vitamin C, ceruloplasmin and reduced glutathione (GSH). To assess the extent of oxidative stress, the levels of lipid peroxidation (LPO) and hydroperoxides in both plasma and pancreatic tissues were also measured. A significant increase in the levels of both lipid peroxides and hydroperoxides with a concomitant decrease in antioxidant status was observed in the diabetic rats when compared to control rats. Oral administration of D-Pinitol (50 mg/kg b.w./day for 30 days), a major cyclitol present in soybean, ameliorates the free radical-mediated alterations to near normalcy. The pancreatic tissue protective nature of D-Pinitol was further evidenced by histological observations. The results were statistically comparable with glyclazide, a standard hypoglycemic drug. Thus, the results of the present study suggest that D-Pinitol protects the pancreatic tissue from free radical-mediated oxidative stress in addition to its antidiabetic property.     

Antihyperglycemic,antihyperlipidemic and antioxidant activities of polysaccharides from Catathelasma ventricosum in streptozotocin-induced diabetic mice

It is the first time to extract polysaccharides (CVPs) from Catathelasma ventricosum. The antihyperglycemic and antioxidant activity of CVPs in streptozotocin-induced diabetic mice were examined. Compared with untreated diabetic mice, the administration of CVPs for 30 days caused a significant decrease in the concentrations of blood glucose, total cholesterol (TC), triglycerides (TGs), low-density lipoprotein-cholesterol (LDL-C) and maleic dialdehyde (MDA), and a significant increase in the concentrations of high density lipoprotein-cholesterol (HDL-C) and the activities of antioxidant enzymes. Specially, when normal mice were treated with CVPs, all detection indexes and pathologic morphologies of liver, kidney and pancreas are similar to untreated normal mice, which indicated CVPs are safe for normal mice. In addition, the average molecular weight of CVPs was estimated to be from 3.7 × 10³ to 1.7 × 10⁷ Da and they were mainly composed of glucose (93.5%) with the conformation of α-d-Glucopyranose.     

Tolerance to dichloroacetonitrile-induced neurotoxicity in streptozotocin-induced diabetic rats

Diabetes mellitus has potential to alter the toxicity of hazardous chemicals. Dichloroacetonitrile (DCAN) is one of high-risk nitrogenous disinfection by-products. This study evaluated the neurotoxicity of DCAN (11, 44 and 88 mg/kg) in normoglycaemic and streptozotocin (STZ)-induced diabetic rats via orally for 28 days. STZ diabetes prolonged the median survival time and total lethal time after DCAN (88 mg/kg) exposure when compared with that observed in normoglycaemic rats. DCAN altered motor activity and induced anxiety behaviour in normoglycaemic rats; but it did not exaggerate behavioural changes in STZ diabetic rats. DCAN –induced brain oxidative damage by compensatory increase glutathione content and decrease malonaldehyde levels; but it did not induce oxidative damage in diabetic rats. STZ diabetes slowed down the pathological pace of DCAN-induced brain mitochondrial dysfunction by decreasing reactive oxygen species and increasing cytochrome C oxidase activity. In conclusion, the present study indicated that STZ diabetic rats are resistant to DCAN-induced neurotoxicity at the dosage and with the dosage schedule in 28-day subacute toxicity test.     

Early oxidative stress in testis and epididymal sperm in streptozotocin-induced diabetic mice: its progression and genotoxic consequences

Experimental induction of diabetes mellitus in animal models using chemical diabetogens is demonstrated to impair testicular function progressively leading to decreased fertility. Although, both steroidogenic and spermatogenic dysfunctions have been reported, the role of oxidative stress mechanism/s has been less understood. We have investigated the induction of oxidative damage during early diabetic phase in testis and epididymal sperm (ES) in mice administered an acute dose of streptozotocin (STZ). Our results show enhanced lipid peroxidation in testis (cytosol and mitochondria) and ES and increased ROS production as early as 5 days. Further, significant perturbations in the activities of antioxidant enzymes in testis/ES and enhanced protein carbonyl content were suggestive of increased oxidative stress during early diabetic phase. STZ-induced oxidative damage in both compartments was amenable for attenuation by treatment with oral supplements of either ascorbic acid (10 mg/(kg(bw) day)) or taurine (1 g/(kg(bw) day)). Furthermore, the oxidative impairments in testis/ES were persistent during the progressive phase (as measured at 2 and 4 weeks of sampling) and were associated with significant increase DNA damage (testis) and higher incidence of abnormal sperms. Interestingly, mating of STZ treated males sequentially for a period of 5 weeks with virgin untreated females resulted in a significant increase in the male-mediated dominant lethal-type mutations during the first 3 weeks, indicating a stage-specific genotoxic effect on post-meiotic germ cells. Based on the occurrence of oxidative impairments in STZ-treated mice both during both early and progressive phase, it is hypothesized that oxidative stress mechanisms may be wholly or in part contribute towards the development of testicular dysfunction and degeneration under situations of experimentally induced diabetes in animal models.     

Effect of Kombucha,a fermented black tea in attenuating oxidative stress mediated tissue damage in alloxan induced diabetic rats

Diabetic complications associated with increased oxidative stress can be suppressed by antioxidants. In the present study we investigated the antidiabetic and antioxidant effects of Kombucha (KT), a fermented black tea, in comparison to that of unfermented black tea (BT), in ALX-induced diabetic rats. ALX exposure lowered the body weight and plasma insulin by about 28.12% and 61.34% respectively and elevated blood glucose level and glycated Hb by about 3.79 and 3.73 folds respectively. The oxidative stress related parameters like lipid peroxidation end products (increased by 3.38, 1.7, 1.65, 1.94 folds respectively), protein carbonyl content (increased by 2.5, 2.35, 1.8, 3.26 folds respectively), glutathione content (decreased by 59.8%, 47.27%, 53.69%, 74.03% respectively), antioxidant enzyme activities were also altered in the pancreatic, hepatic, renal and cardiac tissues of diabetic animals. Results showed significant antidiabetic potential of the fermented beverage (150 mg lyophilized extract/kg bw for 14 days) as it effectively restored ALX-induced pathophysiological changes. Moreover, it could ameliorate DNA fragmentation and caspase-3 activation in the pancreatic tissue of diabetic rats. Although unfermented black tea is effective in the above pathophysiology, KT was found to be more efficient. This might be due to the formation of some antioxidant molecules during fermentation period.     

Exenatide对糖尿病大鼠认知功能的改善作用及机制研究

目的探讨Exenatide对糖尿病大鼠认知功能的改善作用及机制。方法SD大鼠随机分为正常组、糖尿病组(DM组)及Exenatide给药组(Ex+DM组)。Ex+DM组给药16周,水迷宫检测认知功能;电镜观察海马超微结构;检测与认知相关的p-tau(s202、s396)蛋白表达水平及氧化应激相关指标。结果与DM组比,Ex+DM组糖脂代谢、学习记忆能力、海马超微结构和氧化应激损伤改善,海马p-tau蛋白降低。结论Exenatide改善糖尿病大鼠认知功能,可能与改善糖脂代谢及海马氧化应激有关。     

Effect of treatment with vitamin D plus calcium on oxidative stress in streptozotocin-induced diabetic rats

Background

In diabetes mellitus, uncontrolled hyperglycemia has been reported to induce oxidative stress, which may lead to health complications. Vitamin D, however, acts as a non-enzymatic antioxidant to protect cells against oxidative stress and damage.

Hypoglycaemic effect of Melothria heterophylla in streptozotocin-induced diabetic rats

Context: In the Indian traditional system of medicine, Melothria heterophylla (Lour.) Cogn., (Cucurbitaceae) is prescribed for the treatment of diabetes mellitus.

Objective: In the present study, the antidiabetic effect of ethanol extract of Melothria heterophylla (EEMH), and its active isolated constituents were investigated in streptozotocin (STZ)-induced diabetic Swiss albino rats.

Method: Successive Soxhlet extraction of the dried total aerial parts with petroleum ether for defatting and then with ethanol (95%) to obtain ethanol extract, which was concentrated under reduced pressure. Hyperglycemia was induced in rats by STZ (50 mg/kg, body weight). Twenty-four hours after STZ induction, respective groups of diabetic rats received EEMH (200 and 400 mg/kg, body weight), gallic acid (GA) (2 and 4 mg/kg, body weight), and rutin (RU) (2 and 4 mg/kg, body weight), respectively, orally daily for 15 days. Glibenclamide (0.5 mg/kg, orally) served as reference. Blood glucose levels and change in body weight were measured on every 5^th day during 15 days of treatment. Biochemical parameters, viz., serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP) and serum insulin, were measured.

Results: EEMH and its active constituents significantly (p < 0.01) normalized blood glucose levels and serum biochemical parameters as compared to those of STZ controls. Both GA (4 mg/kg) and RU (4 mg/kg) exhibited maximum glucose lowering effect (69.1 and 66.7%, respectively) in diabetic rats compared to the other dose (2 mg/kg) at the end of the study. EEMH, gallic acid and RU also showed significant increase in serum insulin, and body weight of STZ-induced diabetic rats.

Conclusion: Therefore, ethanol extract of Melothria heterophylla, GA and RU demonstrated remarkable antidiabetic activity in STZ-induced diabetic rats.     

TRPV亚型mRNA在链脲佐菌素诱导的糖尿病大鼠膀胱的表达

目的研究在链脲佐菌素(STZ)诱导的糖尿病大鼠模型的膀胱中瞬时感受器电位V型(TRPV)亚型的mRNA水平是否发生改变,并探究改变的TRPV亚型的mRNA水平是否对糖尿病引起的膀胱功能障碍有影响。方法雄性Wistar大鼠随机分成STZ诱导的糖尿病组,5%蔗糖水诱导的多尿组以及正常对照组。于诱导糖尿病后2,4,8,16和24周进行相关检查。通过尿流动力学检查对膀胱功能进行评价;应用实时定量聚合酶链反应(real-time PCR)方法检测膀胱组织中TRPV亚家族mRNA的表达水平。结果与其他2组相比,除了糖尿病诱导后2周外,其他时间点糖尿病组TRPV1和TRPV4的mRNA水平明显降低;糖尿病组的TRPV2mRNA水平明显高于其他2组,糖尿病诱导后的24周除外;糖尿病诱导后的4,8周的糖尿病组TRPV3mRNA水平以及诱导后2,4,8周的糖尿病组TRPV5mRNA水平明显高于其他2组,在诱导后16,24周糖尿病组TR-PV3和TRPV5mRNA水平明显低于其他2组;在大鼠膀胱中没有TRPV6mRNA的表达。结论由于糖尿病的影响,大鼠膀胱中TRPV亚型的mRNA水平发生了显著变化,这些变化很可能促成了糖尿病大鼠的膀胱功能障碍的发生。     

文蛤不同极性提取物对糖尿病小鼠降血糖作用的研究

目的 利用糖尿病小鼠模型对文蛤提取物的降血糖活性进行初步评价。方法 采用不同极性的溶剂对文蛤进行分级提取,获得文蛤不同极性的提取物;采用高脂饲料喂养联合连续小剂量注射链脲佐菌素(STZ)的方法建立糖尿病小鼠模型,喂饲文蛤不同极性提取物。结果 经过4周喂饲,与模型组相比,阳性对照组、文蛤水提物高低剂量组小鼠的空腹血糖值(FBG)显著降低,且有剂量相关性,文蛤石油醚提取物和甲醇提取物高剂量组小鼠FBG降低;文蛤水提物、甲醇提取物、石油醚提取物组小鼠空腹胰岛素(FINS)水平升高,糖化血红蛋白量(HbA1c)甘油三酯(TG),总胆固醇(TC)水平降低,高密度脂蛋白胆固醇(HDL-C)含量升高。结论 文蛤水提物能降低糖尿病小鼠血糖,文蛤石油醚提取物和甲醇提取物具有降低小鼠血糖的趋势。     

Antidiabetic effect of Streblus asper in streptozotocin-induced diabetic rats

Context: In the Indian traditional system of medicine, Streblus asper Lour (Moraceae) is prescribed for the treatment of diabetes mellitus.

Objective: In the present study, α-amyrin acetate isolated from S. asper, and the petroleum ether extract of S. asper stem bark (PESA) was screened for their antidiabetic properties in streptozotocin (STZ)-induced diabetic rats.

Materials and methods: Successive Soxhlet extraction of the dried stem bark with petroleum ether and then with ethanol (95%) yielded petroleum ether and ethanol extracts, respectively, which were concentrated under reduced pressure. Hyperglycemia was induced in rats by STZ (50?mg/kg, b.w.). Twenty-four hours after STZ induction, respective groups of diabetic rats received PESA (100, 250 and 500?mg/kg, b.w.) and α-amyrin acetate (25, 50 and 75?mg/kg, b.w.) respectively, orally daily for 15 days. Glibenclamide (0.5?mg/kg, orally) served as a reference. Blood glucose levels were measured on every 5th day during the 15 days of treatment. The serum lipid profiles and biochemical parameters, viz., serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP), insulin and glycosylated hemoglobin level, were measured.

Results: PESA significantly (p < 0.01) normalized blood-glucose levels and serum biochemical parameters as compared with those of STZ controls. α-Amyrin acetate (75?mg/kg, b.w.) exhibited maximum glucose lowering effect (71.10%) in diabetic rats compared to the other dose (25, 50?mg/kg) at the end of the study. The protective effect was further confirmed by histopathological examination of the liver.

Conclusion: PESA and α-amyrin acetate demonstrated remarkable antidiabetic activity in STZ-induced diabetic rats.     

Dysfunction of aorta involves different patterns of intracellular signaling pathways in diabetic rats

Rat models of insulin-dependent (streptozotocin-induced) and independent (Otsuka Long-Evans Tokushima Fatty (OLETF)) diabetes had sustained and transient increases in blood glucose levels. Over-contraction due to norepinephrine was seen exclusively in streptozotocin rat aorta. Contraction was enhanced under high-glucose conditions in OLETF rats. In order to understand the association between these patterns of changes, total diacylglycerol was measured as a key element of phosphatidylinositol-turnover due to the conversion of some incorporated glucose into diacylglycerol. Streptozotocin rats had enhanced basal diacylglycerol. Both diacylglycerol kinase (metabolic enzyme of diacylglycerol) and total phosphatidylinositol turnover activities also increased on norepinephrine stimulation, independent of extracellular glucose level. On the other hand, diacylglycerol, diacylglycerol kinase and phosphatidylinositol turnover in OLETF rats increased under high glucose conditions in the absence of norepinephrine treatment. These results indicated that diacylglycerol and diacylglycerol kinase-mediated phosphatidylinositol turnover acceleration was influenced by an increase in glucose levels in OLETF rats or by receptor-mediated signals in streptozotocin rats including glucose desensitization based on submaximal incorporation. We suggest that the alteration of vascular dysfunction is induced by different factors in each type of diabetes.     

Chronic epigallocatechin-gallate improves aortic reactivity of diabetic rats: Underlying mechanisms

Diabetes mellitus is associated with major cardiovascular risk factors which are responsible for excess morbidity and mortality. Green tea catechins including epigallocatechin-3-gallate (EGCG) could exert beneficial health effects to ameliorate cardiovascular and metabolic diseases. Thus, the effect of chronic administration of EGCG was studied on aortic reactivity of streptozotocin (STZ)-diabetic rats. Male diabetic rats received EGCG 25 mg/kg/day for 8 weeks 1 week after diabetes induction. Contractile responses to KCl and phenylephrine (PE) and relaxation responses to acetylcholine (ACh) and sodium nitroprusside (SNP) were obtained from aortic rings. Maximum contractile response of endothelium-intact rings to KCL and PE was significantly lower in EGCG-treated diabetic rats relative to untreated diabetic ones. Endothelium removal abolished the significant difference between EGCG-treated and untreated diabetic groups regarding contractile response to KCl and PE. Meanwhile, endothelium-dependent relaxation to ACh was significantly higher in EGCG-treated diabetic rats as compared to diabetic ones. Pretreatment of rings with N(omega)-L-arginine methyl ester (L-NAME) and indomethacin (INDO) significantly attenuated the observed responses. Meanwhile, two-month diabetes resulted in an elevation of malondialdehyde (MDA) and decreased superoxide dismutase (SOD) activity in aortic tissue and EGCG treatment attenuated the increased MDA content and reduced activity of SOD. Therefore, chronic treatment of diabetic rats with EGCG could prevent the abnormal functional changes in vascular reactivity in diabetic rats through nitric oxide- and prostaglandin-dependent pathways and via attenuation of aortic lipid peroxidation.     

Role of modulation of vascular endothelial growth factor and tumor necrosis factor-alpha in gastric ulcer healing in diabetic rats

The aim of the present study was to assess the effect of drugs that increase gastric vascular endothelial growth factor (VEGF) and suppress gastric tumor necrosis factor-alpha (TNF-α) in gastric ulcer healing in streptozotocin-induced diabetic rats. Sixty male albino rats were made diabetic by intraperitoneal (i.p.) streptozotocin injection and ten rats were injected i.p. by a single dose of saline. Six weeks following streptozotocin or saline injection, gastric ulcers were induced by serosal application of acetic acid. Three days after acetic acid application, rats were divided into: group I (non-diabetic control), group II (streptozotocin-injected), groups III-VII (streptozotocin-injected rats treated with insulin, insulin and pentoxifylline, insulin and simvastatin, pentoxifylline as well as simvastatin, respectively, for 7 days following acetic acid application. The use of insulin, combinations of insulin and pentoxifylline or simvastatin resulted in a significant decrease in gastric ulcer area, significant increase in epithelial regeneration assessed histologically, significant increase in gastric VEGF concentration, and gastric von Willebrand factor (vWF) as well as significant decrease in gastric TNF-α. A significant difference in gastric ulcer area as well as in gastric TNF-α, VEGF and vWF levels could be observed between rats that received combinations of insulin and pentoxifylline or simvastatin compared to rats that received either drug alone. Our results suggest the feasibility of a novel treatment strategy, namely pentoxifylline and simvastatin, for patients in whom impairment of ulcer healing constitutes a secondary complication of diabetes mellitus.     

葛根提取物抗糖尿病大鼠氧化应激的实验研究

目的:探讨葛根提取物防治糖尿病血管病变的机制.方法:采用链脲霉素腹腔注射制备糖尿病大鼠模型,以氨基胍作为阳性药物对照,以葛根总提取物和总黄酮为受试药物,测定各实验组大鼠血糖、超氧化物歧化酶、丙二醛、一氧化氮及一氧化氮合酶,观察葛根提取物对糖尿病大鼠的作用与影响.结果:与正常对照组相比,模型组血糖、血浆超氧化物歧化酶和丙二醛有显著差异(P＜0.05,P＜0.01);葛根总提取物、葛根总黄酮可降低糖尿病大鼠血糖,与模型组比较有显著差异(P＜0.05);氨基胍、葛根总提取物和葛根总黄酮可提高糖尿病大鼠血浆超氧化物歧化酶的活性,减少丙二醛的产生,与模型组比较有显著差异(P＜0.05,P＜0.01).结论:葛根提取物具有抗氧化应激的作用,可防治糖尿病血管病变的发生.     

Arteriolar changes in nitric oxide activity and sensitivity during the course of streptozotocin-induced diabetes

Nitric oxide (NO) may play an important role in the pathogenesis of diabetic microangiopathy. However, arteriolar changes in NO activity and sensitivity to NO may be dependent on both the type of arteriole and the duration of diabetes. Therefore, we assessed, in the in situ spinotrapezius muscle preparation of streptozotocin-diabetic rats and of controls, inside diameters of A2-A4 arterioles and the reactivity to topically applied acetylcholine and nitroprusside, before and after N(G)-nitro-L-arginine (L-NNA) at 2, 4, 6 and 12 weeks of diabetes. In A2 arterioles, basal diameters and the contribution of NO to basal diameter were not affected during the course of streptozotocin-induced diabetes. However, the maximal response to acetylcholine in these arterioles was attenuated after 2 until 4 weeks, and from 4 weeks on a sustained decrease in reactivity to sodium nitroprusside was observed. In A3 arterioles, both the basal diameter and the contribution of NO to basal diameter were decreased after 2 weeks and increased after 6 weeks, while the response to sodium nitroprusside was unaffected. In A4 arterioles, a significant increase in basal diameter was observed after 6 weeks only. Thus, this study shows that streptozotocin-induced diabetes causes microvascular changes in NO activity and sensitivity that depend on the type of arteriole. For each order of arteriole, these changes show a specific pattern during the course of diabetes.     

酮替芬对链脲佐菌素诱导的糖尿病模型大鼠胰岛功能的影响

目的:探讨酮替芬对链脲佐菌素诱导的糖尿病模型大鼠胰岛功能的影响及其作用机制.方法:以高糖高脂饲料对SD大鼠饮食诱导6周,随后一次性i.p.给予链脲佐菌素(STZ)制备糖尿病大鼠模型.模型建立后,实验组给予酮替芬0.09 mg·kg-1·d-1,分别在第0、4、8周宰杀实验大鼠,检测空腹血糖(FBG)、空腹胰岛素(FINS),计算胰岛素敏感指数(ISI)、胰岛素抵抗指数(HOMA-IR),检测炎症因子IL-6、TNF-α,并留取胰腺组织,制片染色进行光镜、电镜观察.分离胰岛细胞线粒体,检测细胞色素C氧化酶(Cytochrome C oxidase,CCO)、琥珀酸脱氢酶(Succinate dehydrogenase,SDH)活性.结果:酮替芬降低糖尿病大鼠的血糖水平(P＜0.05),增加ISI和降低HOMA-IR(P＜0.01),降低IL-6和TNF-α水平,增加胰腺组织中CCO和SDH活性(P＜0.01),还可以改善胰岛细胞形态结构.结论:酮替芬能改善糖尿病大鼠的胰岛功能,其作用机制可能是通过抑制NF-кB激活实现抗炎及改善β细胞线粒体的能量代谢.     

Improvement of biochemical parameters in type 1 diabetic rats after the roots aqueous extract of yacon [Smallanthus sonchifolius (Poepp.& Endl.)] treatment

The aim of this study was to evaluate the effect of yacon (Smallanthus sonchifolius) (Poepp.& Endl.) on clinical parameters under diabetic conditions. The aqueous extract of yacon tuberous roots (YRAE; 0.76 g fructan kg⁻¹ body weight) was prepared at the moment of each administration. Thirty-two male rats were divided into four groups (n = 8): control group (C); group that received YRAE (Y); untreated diabetic group (DM1); and diabetic group treated with YRAE (Y-DM1). The diabetes mellitus was induced by streptozotocin (60 mg kg⁻¹ body weight). The animals from Y2 and Y-DM1 received YRAE by gavage, at 7-day intervals, for 30 days. The aqueous extract of yacon roots decreased (p < 0.05) the water and food intake in diabetic rats (Y-DM1). YRAE treatment reduced (p < 0.05) glycaemia, total cholesterol, VLDL-c, LDL-c and triacylglycerol levels in diabetic rats (YRAE). HDL, urea and creatinine levels did not differ (p > 0.05) between the Y and Y-DM1 groups. YRAE normalised alanine aminotransferase (ALT) activity, when comparing DM1 and Y-DM1 rats, but had no effect on lactate dehydrogenase activity (LDH). In conclusion, YRAE was sufficient for controlling water and food consumption, hyperglycaemia and dyslipidaemia, and promote the reduction of the ALT, suggesting a hepatoprotective effect in rats with STZ-induced DM1.